Means for uniting parts



Aug 21, 1945- i H. J. DAILY 2,383,113

MEANS FOR UNITING PARTS Filed Jan. 16. 1942 ATTORN EY Patented Aug. 21,1945 MEANS FOR UNITING PARTS Hampton Jennings Dailey,-Bloomield, N. J.,as-

signor to Westinghouse Electric Corporation, -East Pittsburgh, Pa., acorporation of Pennsylvania Application January 16, 1942, Serial No.426,965

8 Claims.

This invention relates to means for uniting parts and more especially toan electrical means for uniting bulbous glass parts.

It is common practice in the manufacture of electronic devices toprovide a glass enclosure or envelope, and as the present invention hasparticular utility in connection therewith, the exempliiicationillustrated and described will be directed thereto, but with theunderstanding other uses, embodiments, materials and configurations maybe employed. Accordingly, it may be said that various electronic devicesemploy different sizes and shapes of stems and enelopes, but in mostinstances require sealing or uniting of the envelope portion to the stemportion of the glass after iirst mounting the various electrodes on thestem. This sealing has heretofore been accomplished by melting or fusingthe glass of the two parts at abutting edges with heat from a gas flame.Several disadvantages arise in use of such a dame as a melting means.One is the detrimental effect of the prolonged high temperature upon theelectrode or other internal parts of the device, especially wherephysically close to the joint or line of sealing.` Another disadvantagearises irom the fact a flame-seal is non-homogeneous; the glass melts toa softer consistency and fusing temperature at the outside of its walland is apt to leave a lessflrmly sealed part or even a crevice at theinner side of the wall. Furthermore, use of a iiame for sealingintroduces the necessity of lengthy annealing stages which is alsoaccompanied by oxidation occurring on metallic parts in the device.These and other disadvantages of use of flame-sealing have presented aproblem which this invention has successfully solved.

The objects of the invention may accordingly be generalized as theprovision of a means for overcoming the difficulties and disadvantageslnvolved in connection lwith name-sealing as heretofore employed.

More specifically, an object of the present invention is to obtain auniform seal for the entire thickness of the abutting portions beingsealed.

Another object of the invention is to avoid oxidation and otherdetrimental effects upon parts within the envelope.

Yet another object of the invention is to promote rapidity of sealingand reduction of annealing requirements.

A further object of the invention is to obtain a smooth joint and onewherein no material increase of thickness results.

A-still further object of the invention is to take advantage ofelectrical heating in glass of the RI2 effect and to reduce dielectriclosses adverse to efficient current use.

Additional objects of the invention will appear as the descriptionprogresses, either by direct statement thereof or by implication fromthe-context.

In the accompanying drawing wherein like numerals of reference indicatesimilar parts throughout the several views;

Figure 1 is a sectional View of a portion of an envelope sealed inaccordance with my invention and shown as part of an electron dischargedevice;

Figure 2 is a similar partial section of the envelope in process ofbeing sealed and showing the sealing means associated therewith andmaking initial contact with the envelope;

Figure 3 is a cross-sectional view on line III- III of Fig. 2; andlFigure 4 is a sectional view similar to Fig. 2 and showing the sealingmeans as having completed the sealing of the joint.

'In the speciiic embodiment of the invention illustrated in saiddrawing, an electron discharge device is shown of the type having abowl-like base portion I0 the upper outer edge of which is, in thefinished device, sealed with respect-to an envelope portion II andforming a bulbous enclosure. The base portion Iii is provided with atubulation l2 for exhaust and other purposes, and also is provided withsuitable terminal prongs I3 and lead-in posts Iii sealed with respect tothe base. Certain of the posts carry a transverse plate I5 which ofnecessity is near the region Where the glass has to be sealed. The plateshown constitutes a mounting for a grid I6. Other electrodes, namely acathode I'I and anode I8 are shown associated with said grid as usual.

In normal manufacture, the several prongs, posts, plate and electrodesare assembled with respect to each other and the glass base I0. Then theenvelope portion II is applied with the margin of its open en`dcontiguous to the upper edge of the base. at I9 is then to be sealed bymy improved means. It is to be understood that the base and envelope aresuitably carried coaxially of eaclr other as usual in the lamp machine Mso as to be simultaneously rotated on their common axes. Next thejunction to be sealed is provided a burner 20 for applying a llame '2|to the glass of the envelope and base contiguous to the'junction I9.That burner, representative of as many as may be desired around theenvelope at the stage set- The junction thus presented ting of themachine, is for purposes of preheating the glass in the region of thejunction.

At high temperatures, such as can be accomplished by flame 2l, glassbecomes a partial conductor for electrical current. I utilize thisphenomenon for a useful purpose. The junction is fused into a joint,numeral I9 designating the area of junction and joint. A combinedpartial length of junction and joint is involved in transition fromstatus of junction to status of joint, this cliange of status occurringbetween two brushes 22, 22 which are appropriately remote from eachother both electrically and physically in a direction lengthwise of saidjunction and joint. As high a frequency as is practical to generate isapplied across the said brushes, here depicted as accomplished bytransformer 23. The circuit includes the portion of the heated glassintervening between the brushes, and due to the RI effect in the glass,the glass at the combined partial length of junction and joint betweenthe brushes becomes heated. In order to take advantage of the heatingeifect in the glass, not only of the RP effect, I prefer to use the saidhighest practical frequency, as stated, so as to take advantage of thedielectric losses which are proportional to frequency.

The electric current thus flowing in the glass heats the glass to thefusing temperature, thereby obtaining a unified joint between the twoparts. Since the current flows throughout the thickness of the glass,the seal effected at the inner periphery is as secure and continuous asthe seal at the outer circumference. Furthermore the heating by currentflow and opposing resistance in the glass obtains intense heat whereneeded, evenly distributed and highly effective for sealing purposeswithout producing oxidation or other deleterious effects on theelectrodes or other parts of the device. A shorter sealing time isrequired than with the prior art method and apparatus and less annealingis necessitated.

`The specific apparatus here disclosed for accomplishing the method,comprises a movable support, shown as an arm 2l pivoted at 25 with theaforementioned brush 22 carried by the end of the arm nearest the Jointto be sealed. Suitable hlectrical insulation 26 is interposed betweenthe arm and brush. The other end of the arm 24 has"an adjusting bolt 21therethrough adapted to be engaged by a retractable spring actuatedplunger 2l. Spring 29 actuating the plunger is representative of anysuitable means for applying desired pressure to the brush into contactwith the glass. It will be appreciated that the glass softens whenheated, and accordingly pressure of the brushes is limited to avoidundesired deformation of the envelope and base. If desired, air pressurecan be admitted through tubuiation I2 to sufficient extent to counteractthe mechanical pressure of the brushes and prevent undesired indentationof the glass wall while soft.

The facial contour of the brush which is in contact with the glassduring forming operation is preferably shaped to conform to the desiredshape of envelope and base at the joint. In the present instance I haveshown the facial contour of the v engaging portion to be, in section,concave, so that,

with the gloss softened and rotating, a rounded peripheral shoulder isproduced on the envelope. l'he final glass shape desired will be that ofthe concave face of the brush.

The brush preferably provides a current conducting area It and a.4non-conducting area 3|. Since the heating will take place in the glassover a wider area than the conducting contact surface 2,sss,11a

of the brush, the non-conducting areas avoid increasing the heated areaand obtain a smoothing guiding contact with a part of the glass which iscooler and more resistant to pressure.

Accordingly the portions 0f the brush, at top and bottom thereof,preferably are comprised of electrically insulative and heat resistantmaterial and each forms a continuation of the glass engaging face orarea of the metallic or conductive part of the brush and along the edgesof the brushes paralleling the junction and joint. This arrangementaccomplishes a smoothing engagement without carrying the conductive andheating contact over as extensive an area. 4It is appropriate to mentionat this point that the parts to be sealed do not have to be at a corner,but a Joint may be made wherever desired, the face areas of the brushbeing shaped accordingly.

In operation, the electronic or other device is applied in thelamp-making machine and rotated and revolved as familiar to thoseskilled in the art. At each stage of the revolving cycle, an appropriatefabricating step is performed. It is preferably to apply flame or flames2l to the junotion area at one stage of revolution and there preheat theglass. The electrical brushes may, if desired, be in contact with theglass during this preheating stage and continue the heating immediatelythe glass becomes hot enough to pass the applied high frequency current.However, it is within the scope of the invention to apply the preheatingby flame 2i at one stage of the rotative cycle of the machine, and applythe high frequency current heating at the following stage. The importantfactor is that the high frequency current flows in the glass for thefull thickness of the wall thereof so that a homogeneous seal isobtained without any crevice occurring. The current flow within theglass itself concentrates the heating effect in the glass and with leastdetrimental effect upon closely associated metallic parts, such as plateI5, and furthermore heats quickly and requires minimum annealing time orattention.

Since the various details of construction and steps involved in themethod, as well as the precise relation and functioning of parts aresubject to variation and change without departing from the inventiveconcept or scope of the invention, it is intended that all mattercontained in the specification or illustrated inthe drawing, shall beinterpreted as exemplaryv and not in a limiting sense. It is also to beunderstood that the following claims are intended to cover all of thegeneric and specific features of the invention herein shown anddescribed and all statements of the scope of the invention herein setforth as a matter of language which might be said to` fall therebetween.

I claim:

1. A means for sealing a junction between glass parts of a bulbousenclosure to formy a closed joint .thereat, comprising means for makingelectrical contact with the glass contiguous to the junction and jointand at parts separated lengthwise of the junction and joint, said meanshaving a surface portion for making surface contact with the glass onboth sides oi the joint, and. said means having electricallynonconducting areas toward the glass and forming part of said surfacefor making guiding contact with the glass.

2. A means for sealing a junction between glass parts of a. bulbousenclosure to form a closed joint thereat, comprising means for makingelectrical contact with the glass contiguous to the junction and jointand at pax-ts separated lengthwise of the junction and joint, said meanshaving a surface portion for making surface contact with the glass onboth sides of the joint, and said means having electricallynon-conducting areas toward the glass at edges of said surface portionmaking guiding contact wi-thv the glass and at a part of said surfaceportion most remote from the joint-engaging part of said means.

' 3. A means for sealing a junction between glass parts of .a bulbousenclosure to form a closed joint thereat, comprising means for makingelectrical contact with the glass contiguous to the junction and jointand at parts separated lengthwise of the junction and joint, said meanshaving a conducting portion for making surface contact with the glass onboth sides of and in parallelism to the joint, and said means havingelectrically non-conducting areas at edges of said conducting portiontoward Ithe glass and paralleling said conducting portion in parallelismto the junction, said non-conducting areas being in surface continuationwith the surface contacting area of the electrically conductive portionof said means.

4. A means for sealing a junction between a glass envelope and a glassbase to iorm a closed joint thereat, comprising in combination withmeans for rotating the junction and joint, means for making electricalcontact with the glass contiguous to said junction and joint, means forsupplying high frequency current to said con-- tact means andprogressively along 'the junction and joint for heating Ithe said glasscontiguous to and progressively of said junction and joint to fusingtemperature, and meansfor pressing the electrical contact means towardthe juncture at the area of contact with the glass contiguous to andprogressively of the junction and toward and progressively of .the jointat the area of contact with the glass contiguous to the joint forsimultaneously fusing the glass next the joint and smoothing the jointas fused.

5. A means for sealing a junction between a glass envelope and a glassbase .to form a closed joint thereat, comprising in combination withmeans for rotating the junction and joint, means for making electricalcontact with the glass contiguous to and at parts separated lengthwiseof said junction and joint, means for supplying high frequency currentto said contact means to flow through the glass separating said contactmeans lengthwise of the junction and joint for heat-.-

l trical contact with .theglass contiguous to the junction and joint andat parts separated lengthwise of a combined partial length of thejunction and joint, said means having a portion making surface contactwith the glass on both sides of the junction and joint, and said meanshaving electrically non-conducting areas in contact with the glass inparallelism .to and spaced from the joint, and means for pressing theelectrical contact means .toward the joint for simultaneously fusing theglass next the joint and smoothing the joint as fused.

7. A means for sealing a junction between glass parts of a bulbousenclosure to form a closed joint thereat, comprising means for makingelectrical contact with the glass contiguous to the junction and jointand at parts separated lengthwise of the junction and joint, said meanshaving a portion making surface contact with the glass on both sides ofthe joint, and said means so having electrically non-conducting areastoward the glass at edges of said portion making contact with the glassin parallelism to and spaced from the joint, and means for pressing theelectrical contact means toward the glass for simultaneously fusing theglass next the joint and smoothing the joint as fused.

8. A means for sealing a junction between glass parts of a bulbousenclosure to form a closed joint thereat, comprising means for makingelectrical contact with the glass contiguous to the junction and jointand at parts separated lengthl wise of the junction and joint, saidmeans having a portion making surface contact with the glass on bothsides of the junction and joint, and said means having electricallynon-conducting areas at edges paralleling the junction and toward theglass, said non-conducting areas being in surface continuation with thesurface contacting area of the electrically conductive portion thereof,and means for pressing :the electrical contact means toward the glassfor simultaneously fusing the glass next the joint and smoothing thejoint as fused. v

HAMPTON JENNINGS DAILEY.

